Selective power-on of hard disk drives within and across multiple drive enclosures and power supply domains

Abstract

To prevent current inrush from exceeding power limitations of a power supply or a power domain in a multiple disk drive system the drives are powered-on in a controlled sequence. In a multi-drive blade storage subsystem, a subsystem control module inventories the locations of the hard drives in one or more drive enclosure blades and maintains information about the boundaries of one or more power domains. The subsystem control module may direct one of several drive power-on sequences, none of which allow current inrush to exceed the allowable current of each power domain.

1 . A method for managing the power-on of multiple hard disk drives (HDDS) in a storage subsystem, each HDD being housed within one of at least one drive enclosure module and being associated with a power domain within the subsystem, the method comprising:
 receiving a signal to power-on the HDDs in the subsystem;   accessing a table identifying the location of each HDD in the system, the location including the identity of a drive enclosure module in which each is housed and the power domain with which each HDD is associated; and   directing each drive enclosure module to power-on the housed HDDs.   
   
   
       2 . The method of  claim 1 , further comprising, prior to accessing the table, performing a discovery operation to identify the number and location of each HDD in the subsystem and generating the table. 
   
   
       3 . The method of  claim 1 , wherein directing each drive enclosure module to power-on the housed HDDs comprises directing one or more drive enclosure modules at a time to power-on the housed HDDs whereby current drawn by the HDDs remains within a maximum current limitation of each power domain. 
   
   
       4 . The method of  claim 3 , further comprising directing each drive enclosure module to power-on one or more selected HDDs at a time within the drive enclosure module. 
   
   
       5 . The method of  claim 1 , wherein directing each drive enclosure module to power-on the housed HDDs comprises directing one drive enclosure module in each power domain at a time to power-on the housed HDDs whereby current drawn by the HDDs remains within a maximum current limitation of each power domain. 
   
   
       6 . The method of  claim 1 , wherein directing each drive enclosure module to power-on the housed HDDs comprises:
 directing a first drive enclosure module to power-on;   waiting until a resulting current spike dissipates; and   directing a second drive enclosure module to power-on.   
   
   
       7 . A storage subsystem, comprising:
 at least one redundant pair of power supply units (PSUs);   at least one pair of power buses corresponding to the at least one pair of redundant PSUs, a first of each redundant pair of PSUs coupled to provide power to a first of the corresponding pair of power buses and a second of each redundant pair of PSUs coupled to provide power to a second of the corresponding pair of power buses, each pair of power buses defining a power domain;   a plurality of slots to receive modules, each slot redundantly coupled to both buses in a power domain whereby power is receivable from both PSUs of a redundant pair of PSUs;   at least one drive enclosure module: each drive enclosure module inserted into one or more slots and comprising a plurality of hard disk drives (HDDS), each HDD being associated with a power domain and redundantly coupled to both buses in the power domain whereby power is receivable from both PSUs of a redundant pair of PSUs;   a master power controller coupled to the drive controller in each drive enclosure module, the master power controller comprising:
 means for receiving a power-on signal, 
 a table identifying the location of each HDD in each drive enclosure module, including the identity of the power domain with which each HDD is associated; and 
 means for transmitting a command to each drive enclosure module to power-on the associated HDDs; and 
   each drive enclosure module further comprising a local power controller, responsive to the command from the master power controller for powering on the associated HDDs.   
   
   
       8 . The storage subsystem of  claim 7 , wherein the master power controller comprises a SCSI enclosure services (SES) component within a serial attached SCSI (SAS) switch. 
   
   
       9 . The storage subsystem of  claim 7 , wherein:
 the HDDs comprise a RAID array; and   the master power controller comprises an SES component within a RAID controller.   
   
   
       10 . The storage subsystem of  claim 7 , wherein the local power controller comprises a local SES component. 
   
   
       11 . The storage subsystem of  claim 7 , wherein:
 the storage subsystem comprises blade architecture;   the master power controller is selected from a group comprising an SES component within an SAS switch and an SES component within a RAID controller, and   the local power controller comprises a local SES component.   
   
   
       12 . The storage subsystem of  claim 7 , wherein the command to each drive enclosure module comprises a command directing one local power controller at a time to power-on the associated HDDs whereby current drawn by the HDDs remains within a maximum current limitation of each power domain. 
   
   
       13 . The storage subsystem of  claim 12 , wherein the command to each drive enclosure further comprises a command directing the drive enclosure module to power-on one or more selected HDDs at a time within the drive enclosure module. 
   
   
       14 . The storage subsystem of  claim 7 , wherein the command to each drive enclosure module comprises a command directing one local power controller in each power domain at a time to power-on the associated HDDs whereby current drawn by the HDDs remains within a maximum current limitation of each power domain. 
   
   
       15 . The storage subsystem of  claim 7 , wherein the master power controller further comprises means for detecting a hot-plug signal. 
   
   
       16 . A computer program product of a computer readable medium usable with a programmable computer, the computer program product having computer-readable code embodied therein for managing the power-on of multiple hard disk drives (HDDs) in a storage subsystem, each HDD being housed within one of at least one drive enclosure module and being associated with a power domain within the subsystem, the computer-readable code comprising instructions for:
 receiving a signal to power-on the HDDs in the subsystem;   accessing a table identifying the location of each HDD in the system, the location including the identity of a drive enclosure module in which each is housed and the power domain with which each HDD is associated; and   directing each drive enclosure module to power-on the housed HDDs.   
   
   
       17 . The computer program product of  claim 16 , the computer-readable code further comprising instructions for performing a discovery operation to identify the number and location of each HDD in the subsystem and generating the table prior to accessing the table. 
   
   
       18 . The computer program product of  claim 16 , wherein the instructions for directing each drive enclosure module to power-on the housed HDDs comprise instructions for directing one drive enclosure module at a time to power-on the housed HDDs whereby current drawn by the HDDs remains within a maximum current limitation of each power domain. 
   
   
       19 . The computer program product of  claim 18 , the computer-readable code further comprising instructions for directing each drive enclosure module to power-on one or more selected HDDs at a time within the drive enclosure module. 
   
   
       20 . The computer program product of  claim 16 , wherein the instructions for directing each drive enclosure module to power-on the housed HDDs comprise instructions for directing one or more drive enclosure modules in each power domain at a time to power-on the housed HDDs whereby current drawn by the HDDs remains within a maximum current limitation of each power domain.